Ethylene derivatives aldehydes, synthesis

Aldehydes from ethylene derivatives Synthesis with addition of 1 C-atom... 

Stannous fluoride Knoevenagel condesation Synthesis of ethylene derivatives from aldehydes and hydrocarbons... 

Benzoyl peroxide Synthesis of ketones from aldehydes and ethylene derivatives... 

Wittig synthesis with As-ylids Synthesis of rraw -ethylene derivs. or trans Oxido compds. from aldehydes and arsonium salts... 

Wittig synthesis with As-yiides Ethylene derivatives from aldehydes Arsonium salts... 

The first total synthesis of cinchonamine (277) and 2-epicinchonamine (278) proceeds via the epimers (279), which were prepared by two independent methods.169 Scheme 28 illustrates the more efficient of the two syntheses, which involves as its first stage the condensation of 2-lithio-iV-benzenesulphonyl-indole with N-benzoylmeroquinene aldehyde (280), itself obtained by reduction of the readily available JV-benzoylmeroquinene ester (281). The critical cyclization stage [(279)— (283)+ (284)] that occurs on prolonged heating at 155 °C presumably proceeds via the immonium ion (282), since separation of the epimers of (279) followed by dehydration and cyclization affords the same mixture of (283) and (284). Finally, the hydroxyethyl group was introduced by the reaction of the Grignard derivatives of (283) and (284) with ethylene oxide.169... 

This is the simplest case of the reaction but it has been mostly used in the synthesis of higher members of the unsaturated acid series, e.g., the nine carbon acid, nonylenic acid, which is prepared from the seven carbon aldehyde known as oenanthylic aldehyde, or oenanthol, obtained from castor oil. Even more important than its application in the synthesis of higher acids of the ethylene series is the use of the reaction in the synthesis of aromatic unsaturated cLcids derived from benzene and containing an unsaturated side chain (see cinnamic acid. Part II). The reaction is known as the Perkin Synthesis or as the Perkin-Fittig Synthesis from the men who suggested and explained it. 

This sequence transforms acyclic ketones and aldehydes into a-methylene ketones and a-methyl-a,)5-unsaturated ketones and aldehydes It has been illustrated by the synthesis of eucarvone, ( )-nuciferal and ( )-manicone This ring-opening of chlorosiloxycyc-lopropanes with ClSiMea elimination appears to be a practical route to Z or a,)5-ethylenic aldehydes and ketones depending on the stereochemistry of the reactants. For example, conversion in MeOH-NEta at 20°C of the 2-chloro-2-methyl-3-pentyl-l-trimethylsiloxycyclopropanes (derived from the addition of the chloromethylcarbene to the E and Z silyl enol ethers of n-heptanal) leads either to or Z 2-methyl-oct-2-enal (equation 65). ... 

In a paper published along with that of Stevens and Wentland20 and in agreement with these authors, Keely and Tahk23 reported the independent synthesis of dl-mesembrine, also from I-methyl-3-(3,4-dimethoxyphenyl)-2-pyrroline and methyl vinyl ketone. In their work the cyclopropyl derivative 3b was prepared from the reaction of the anion of 3,4-dimethoxyphenylacetonitrile (lc) with ethylene dibromide in dimethyl sulfoxide and its sodium salt as solvent and base. Reduction with ethereal diisobutylaluminum hydride gave the aldehyde, which was condensed with excess methylamine in benzene-ether solution with calcium oxide as the dehydrating agent. 

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